Though I usually dislike animal-commoner analogies, it will work here. Many modern people support rules against animal cruelty, probably most modern people. Not all modern people believe in animal rights (exhibit 1: me). It is common to believe in rules of behavior and treatment even in regards to entities we do not regard as having fundamental rights.
I fully agree that any consciousness or philosphy of equality amongst species didn't take place as a majority in society until just recently in western human history, as far as i know.
I do am saddened and astounded by the fact that there are 'learned' people who'd still think the same after so much astonishing development in publicly accessible sience and knowledge during the past 200/300 years and especially the last 20 with the internet.
Even after Darwins origin of species and so much great philosophers during and after contributed so much, there are people who think that humans are IT, the final stage of evolution, perfection, the only true child of god as the christian church indoctrinated us for so many centuries.
Above all the other species, who are in many different kind of ways, MUCH more perfect than us!
You might laugh now, but lets see who will have the LAST laugh...